The invention discloses a method for measuring the void ratio of a cigarette capsule. The measuring method comprises the following steps: (1) detecting the external tangent volume of a to-be-measured cigarette capsule by a three-dimensional measuring device; (2) unpacking the to-be-measured cigarette capsule, finding an arrangement model of cigarettes in the to-be-measured cigarette capsule in a preset cigarette arrangement model base according to the arrangement condition of the cigarettes in the capsule, measuring the diameters and lengths of the cigarettes, and calculating the initial packaging volume of the cigarette capsule; and (3) substituting the external tangent volume and the initial packaging volume of the capsule in a formula shown in the specification to obtain the void ratio of the cigarette capsule through calculating, wherein the external tangent volume of the capsule is the minimum external tangent cuboid volume of the cigarette capsule, the initial packaging volume of the capsule is the minimum external connecting cube volume occupied by all the cigarettes which are arranged according to the arrangement model in the capsule, and k is a necessary space factor of the cigarette capsule.